A laboratory and clinical evaluation of an immunochemiluminometric assay of thyrotropin in serum.

1988 ◽  
Vol 34 (10) ◽  
pp. 2087-2090 ◽  
Author(s):  
D J Berry ◽  
P M Clark ◽  
C P Price
Keyword(s):  
Magnetic Particles ◽  
Magnetic Particle ◽  
External Quality Assessment ◽  
Limit Of Detection ◽  
Particle Separation ◽  
Reference Interval ◽  
External Quality ◽  
Analytical Recovery ◽  
Luminescence Assay ◽  
Assay Time

Abstract We evaluated an immunochemiluminometric assay for human thyrotropin. A chemiluminescent acridinium ester is used as a label, with magnetic-particle separation. The lower limit of detection of the assay (mean + 3 SD of the zero standard) was 0.07 milli-int. unit/L, with a working range of 0.5 to greater than 60.0 milli-int. units/L. Assay accuracy was good as judged from analytical recovery, analysis of external quality-assessment samples, and comparison with an enzyme-amplified immunoassay. There were no significant interferences or cross-reactivities. Twenty-four samples assayed showed aggregation of the magnetic particles. On re-assay, four of these samples showed a significant increase in the measured TSH by the luminescence assay. Assay time for 60 tubes was approximately 3.5 h with the use of a semi-automated luminometer. The reference interval, determined from data on 144 healthy euthyroid subjects, was 0.3-4.0 milli-int. units/L. Sixteen of 19 thyrotoxic patients showed clearly suppressed concentrations of thyrotropin in serum.

Enzyme-amplified immunoassays: a new ultrasensitive assay of thyrotropin evaluated.

1986 ◽  
Vol 32 (1) ◽  
pp. 88-92 ◽  
Author(s):  
P M Clark ◽  
C P Price
Keyword(s):  
Healthy Subjects ◽  
Normal Values ◽  
External Quality Assessment ◽  
Limit Of Detection ◽  
Microtiter Plate ◽  
Front Line ◽  
External Quality ◽  
Analytical Recovery ◽  
Ultrasensitive Assay ◽  
Line Test

Abstract An enzyme-amplified immunoassay for thyrotropin has been evaluated. The lower limit of detection of the assay (mean + 3 SD of the zero standard) was 0.037 milli-int.unit/L and the precision was good, giving a working range of 0.13-24.0 milli-int.units/L. The accuracy of the assay was good, as judged from analytical-recovery experiments, analysis of external quality-assessment samples and comparison with in-house assays. No significant interferences or cross reactivities were identified. Assay of a 25-microL serum sample on the microtiter plate takes 3 h. Values for healthy subjects ranged from 0.4 to 4.0 milli-int.units/L. For 32 thyrotoxic patients thyrotropin concentrations were clearly suppressed and completely distinct from normal values. Patients taking triiodothyronine also showed lower concentrations. The enzyme-amplified immunoassay may thus be a suitable "front line" test for assessing thyroid function.

An automated and compartmented fluidic reactor device for multi-step sample-to-answer processes using magnetic particles

2017 ◽  
Vol 2 (3) ◽  
pp. 349-365 ◽  
Author(s):  
J. Hübner ◽  
R. Heinzler ◽  
C. Arlt ◽  
S. Hohmann ◽  
G. Brenner-Weiß ◽  
...  
Keyword(s):  
Magnetic Particles ◽  
Magnetic Particle ◽  
Particle Separation ◽  
Biotechnological Applications ◽  
Segmented Flow

A benchtop device that combines segmented flow with magnetic particle separation and active resuspension capabilities for biotechnological applications, e.g. biomolecule purification.

Thromboplastin Related Differences in the Determination of International Normalised Ratio: A Cause for Concern?

1994 ◽  
Vol 72 (03) ◽  
pp. 426-429 ◽  
Author(s):  
S Kitchen ◽  
I D Walker ◽  
T A L Woods ◽  
F E Preston
Keyword(s):  
Patient Management ◽  
External Quality Assessment ◽  
Oral Anticoagulant Therapy ◽  
Warfarin Dosage ◽  
External Quality ◽  
External Quality Assessment Scheme ◽  
International Normalised Ratio ◽  
The Uk ◽  
The Relationship

SummaryWhen the International Normalised Ratio (INR) is used for control of oral anticoagulant therapy the same result should be obtained irrespective of the laboratory reagent used. However, in the UK National External Quality Assessment Scheme (NEQAS) for Blood Coagulation INRs determined using different reagents have been significantly different.For 18 NEQAS samples Manchester Reagent (MR) was associated with significantly lower INRs than those obtained using Diagen Activated (DA, p = 0.0004) or Instrumentation Laboratory PT-Fib HS (IL, p = 0.0001). Mean INRs for this group were 3.15, 3.61, and 3.65 for MR, DA, and IL respectively. For 61 fresh samples from warfarin-ised patients with INRs of greater than 3.0 the relationship between thromboplastins in respect of INR was similar to that observed for NEQAS data. Thus INRs obtained with MR were significantly lower than with DA or IL (p <0.0001). Mean INRs for this group were 4.01, 4.40, and 4.59 for MR, DA, and IL respectively.We conclude that the differences between INRs measured with the thromboplastins studied here are sufficiently great to influence patient management through warfarin dosage schedules, particularly in the upper therapeutic range of INR. There is clearly a need to address the issues responsible for the observed discrepancies.

scholarly journals The versatility of external quality assessment for the surveillance of laboratory and in vitro diagnostic performance: SARS-CoV-2 viral genome detection in Austria

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Christoph Buchta ◽  
Jeremy V. Camp ◽  
Jovana Jovanovic ◽  
Peter Chiba ◽  
Elisabeth Puchhammer-Stöckl ◽  
...  
Keyword(s):  
Quality Assessment ◽  
External Quality Assessment ◽  
False Negative ◽  
Positive Sample ◽  
Performance Criteria ◽  
External Quality ◽  
Assay Sensitivity ◽  
Dilution Series ◽  
Test Systems

Abstract Objectives External quality assessment (EQA) schemes provide information on individual and general analytical performance of participating laboratories and test systems. The aim of this study was to investigate the use and performance of SARS-CoV-2 virus genome detection systems in Austrian laboratories and their preparedness to face challenges associated with the pandemic. Methods Seven samples were selected to evaluate performance and estimate variability of reported results. Notably, a dilution series was included in the panel as a measure of reproducibility and sensitivity. Several performance criteria were evaluated for individual participants as well as in the cohort of all participants. Results A total of 109 laboratories participated and used 134 platforms, including 67 different combinations of extraction and PCR platforms and corresponding reagents. There were no false positives and 10 (1.2%) false negative results, including nine in the weakly positive sample (C t ∼35.9, ∼640 copies/mL). Twenty (22%) laboratories reported results of mutation detection. Twenty-five (19%) test systems included amplification of human RNA as evidence of proper sampling. The overall linearity of C t values from individual test systems for the dilution series was good, but inter-assay variability was high. Both operator-related and systematic failures appear to have caused incorrect results. Conclusions Beyond providing certification for participating laboratories, EQA provides the opportunity for participants to evaluate their performance against others so that they may improve operating procedures and test systems. Well-selected EQA samples offer additional inferences to be made about assay sensitivity and reproducibility, which have practical applications.

Harmonising EQA schemes the next frontier: challenging the status quo

2020 ◽  
Vol 58 (11) ◽  
pp. 1795-1797 ◽  
Author(s):  
Tony Badrick ◽  
Anne Stavelin
Keyword(s):  
External Quality Assessment ◽  
Reference Method ◽  
Laboratory Medicine ◽  
Status Quo ◽  
External Quality ◽  
Educational Support ◽  
Laboratory Results ◽  
The Status ◽  
Clinically Significant ◽  
Eqa Schemes

AbstractThere is a focus on standardisation and harmonisation of laboratory results to reduce the risk of misinterpretation of patient results assayed in different laboratories. External quality assessment (EQA) is critical to assess the need for harmonisation and to monitor the success of procedures to achieve harmonisation. However, EQA providers are being stretched to meet the needs of their participants with proven commutable material with reference method targets, a range of clinically significant levels of the materials, detailed and customised data analysis, and educational support. The path ahead for harmonisation of EQA schemes will require leadership from an organisation that has the support and confidence of EQA providers, like the European Organisation for External Qualily Assurance Providers in Laboratory Medicine.

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